writes:
Hi Chris, and all,
Wow!....thanks for the references and all the very patient help. The
Centronic units I have, do have all the characteristics you advise
against....ha...even to the blue enhancement. They are round cans,
and look to be filled with some clear substance that even encases the
photovoltiacs themselves...they can't be salvaged for use...I've
already tried that. The web address is:
http://www.centronic.co.uk
ChrisAtUpw@....... wrote:
Allied at http://www.alliedelec.com/default.asp p563 & 565 have
quite
a few suitable products with planar technology. I use BPW34's which are
similar to the VTD34 980 0150 @ $1.69 that George Harris recommended. I
bought several cells and found that they all matched to a few %.
Yes indeed this all helps....actually it all decidedly enhances the
pursuit
of opto-electronics for overall amateur seismology in my opinion.
Some things were a surprise in their discussion, use and even the
extraordinary logical selection of such. For my current use, I have to
use this approach; as its for a diamagnetic levitated spectoscopic
graphite
rod used as a tiltmeter/seismometer. I'am convinced I need to scrap
some previous electronic parts, and get some better material....the
results
will likely be much more accurate in the overall evaluation experiment,
than what I could dredge up alone...ha.
Many thanks to all,
Meredith Lamb
All this talk about precision matching and ambient light,
spectral response, etc., seems crazy. If you really must use
a photographic system (without film on a drum) why take
a lesson from some age-old aeronautical techiniqes. VOR.
You could put a cheap linear filament bulb (like fish tank
bulbs) inside a rotating can with a vertical slit (aligned with
the bulb filament). Put one photocell close to the can for
a reference signal. As the can rotates you get a timing
pulse... Now you mount one long skinny mirror on the
side of your boom, and another to the base a few inches
away and parallel (so the mirrors are opposing each other).
Mount your second photocell "aimed" into one end of this
"angular amplification channel" at about 45 deg, and the
rotating source similarly at the other end. As the boom moves
it causes the phase angle between the reference pulse and
the detector pulse to change, and the rest is all down hill.
You simply need some circuitry to clean up the pulses, and
thare are many ways you can detect the phase changes. The
nice thing about this method is that ambient light and photo
detector response curves don't matter. Choosing the right
RPM and motor to give stable response would be the
biggest challenge.
Just an idea...
Tom
On Mon, 28 May 2001 22:40:47 -0700 "meredith lamb" <
mlamb1@.........> writes:
Hi Chris, and all,
Wow!....thanks for the references and all the very patient help. =
The=20
Centronic units I have, do have all the characteristics you advise=20
against....ha...even to the blue enhancement. They are round =
cans,=20
and look to be filled with some clear substance that even encases the=
=20
photovoltiacs themselves...they can't be salvaged for use...I've=20
already tried that. The web address is:=20
http://www.centronic.co.uk=
=20
ChrisAtUpw@....... wrote:=20
Allied at http://www.alliedelec.=
com/default.asp=20
p563 & 565 have quite
a few suitable products with planar technology. I use BPW34's=
which=20
are
=
similar to=20
the VTD34 980 0150 @ $1.69 that George Harris recommended. I=20
bought several cells =
and found=20
that they all matched to a few %.
Yes indeed this all=20
helps....actually it all decidedly enhances the pursuit
of=20
opto-electronics for overall amateur seismology in my opinion.
Some =
things=20
were a surprise in their discussion, use and even the
extraordinary=20
logical selection of such. For my current use, I have to
use =
this=20
approach; as its for a diamagnetic levitated spectoscopic graphite
=
rod=20
used as a tiltmeter/seismometer. I'am convinced I need to scrap some=20
previous electronic parts, and get some better material....the results=20
will likely be much more accurate in the overall evaluation =
experiment,=20
than what I could dredge up alone...ha.=20
Many thanks to all,=20
Meredith Lamb=20
=20